Predefined snippets

A feature called Snippets is present in the DevTools which allows you to save (or remove) bits of code which can be run on a webpage (it's just a bit more convenient than re-typing JavaScript code in the console panel). To try it:

Go to Sources > Snippets (it's in the left sidebar)

Right click in the snippets window and select New

Enter a file name and your desired snippet

Right click on the snippet and select Run (or Ctrl/Cmd + Enter)

You'll also notice it has multi-line editing and confirmation for exit-without-saving.